Treatment or production of cellulose derivative materials



105. U ilVllUblllumo,

COATING OR PLASTIC.

ra ed Sept. 1, 1936 UNITED STATES PATENT, OFFICE TREATMENT OR PRODUCTION OF CELLU- LOSE DERIVATIVE MATERIALS Henry Dreyfus, London, England No Drawing. Application May 26, 1930, Serial No. 455,969. In Great Britain July 9, 1929 3 Claims.

This invention relates to new or improved processes for the weighting or mordanting of materials made of or containing cellulose acetate or other cellulose esters or ethers, for example cellulose formate, cellulose propionate, cellulose butyrate, or methyl, ethyl or benzyl cellulose.

It is well-known that the incorporation of metallic radicles in materials made of or containing cellulose esters or ethers has presented considerable difiiculties. In the case of weighting and mordanting metal radicles these difliculties have been overcome by treatment of the filaments, threads, yarns, ribbons, -woven, knitted or other fabrics, or other materials with solutions of salts of the weighting or mordanting metals under such conditions that swelling of the cellulose derivative occurs. The weighting or mordanting metal solution may be applied in such concentrations or under such conditions that it. itself constitutes a swelling agent for 'the cellulose derivative, or alternatively a swelling agent may be incorporated in the solution or may be applied to the material prior to the mordanting or weighting metal solution. On the other hand combinations of these methods may be'employed.

The mordanting or weighting metal may be fixed in the material by a previous or subsequent treatment with a suitable precipitant for the metal salt, for example phosphates, silicates, tannic acid or tannates, or even water containing a little alkali in solution. Numerous prior specifications of British Celanese Limited, R. Clavel and myself describe such processes and these specifications instance as examples of suitable mordanting and weighting metals, aluminum, chromium, iron, tin, zinc, tungsten and bismuth.

I have now found that a very effective mordanting or weighting of such materials may be achieved by incorporating either a precipitant or a compound of the mordant or weighting metal in the spinning solution used in the manufacture of the filaments or other products and treating the products, either subsequent to their production or' or cellulose esters or ethers are mordanted or weighted by precipitating in the materials insoluble mordanting or weighting metal compounds, the mordanting or weighting metal salt or the precipitant necessary for the iormation of, the

metal radicles. I prefer however to incorporate x the mordanting or weighting metal compound it- 'self in the spinning solutions and subsequently to apply the precipitant. As examples of suitable mordanting or weighting metal salts which may be incorporated in the spinning solutions the following may be instanced: stannic chloride, stannic thiocyanate, ferric chloride, ferric thiocyanate, aluminium thiocyanate, zinc chloride, and chromium thiocyanate. 'The proportion of weighting or mordanting metal relative to the cellulose acetate or other cellulose derivative may be varied as-desired. In the case of mordanting, an addition of one to two percent of the mordant metal salt on the cellulose acetate or other cellu'' lose derivative is usually sufficient, while, in the case of Weighting, proportions of 10 to 20% or upwards may be used. The precipitant may be applied either to the finished materials inthread, yarn, fabric or other form or may be applied to the filaments, threads or yarns during or continuously with'their production. For example, the filaments coming from a dry spinning cell may be carried directly into an aqueous bath containing (ii-sodium hydrogen phosphate or containing water having alkali in solution. Water itself may be used as the fixing agent or precipitant, especially in the case of mordant metals, but it is preferable to have a small-amount of alkali, such as ammonia or soda ash, in solution. Again, in the case of wet spinning, the precipitant may be incorporated in the precipitating bath or in a subsequent treatment bath. For the purpose of wet spinning I find that the direct acetylation or other esterification solutions, with or without ripening or further treatment, obtained according to British Patents Nos. 308,322, 308,323 and 309,201 and U. S. Patents Nos. 1,936,586, 1,950,663 and 1,911,069, are particularly suitable. These direct acetylation or esterification solutions already con- 2 tin, and may be spun into precipitating baths containing a precipitant for the metal salt. Mineral acidity or excessive mineral acidity due for example to the use of hydrochloric acid in the esterification or ripening, may be neutralised if desirable or requisite prior to spinning, for instance by adding sodium acetate to the solutions.

The following examples show the best methods known to me for carrying the invention into effect, but they are not to be considered as limiting the invention in any way:-

Example 1 To a 25% solution of cellulose acetate in acetone 12% of stannic thiocyanate calculated on the cellulose acetate is added, and the solution is then spun into filaments by the dry spinning process. The yarn obtained, with or without intermediate washing, is treated for about half an hour at 40 C. in a 12% aqueous solution of disodium hydrogen phosphate, Such treatment may be applied to the goods in the form of hanks or in the form of knitted, woven or'other fabrics or in any other desiredform. The goods may be subsequently soaped in a bath containing 2 /2 grams per litre of soap, rinsed in soft water and dried.

Example 2 A spinning solution is made up with the follow- The solution is then spun into filaments, and the yarn with or without intermediate washing and continuously with production or in a separate operation in the form of hanks, fabrics or in any other form, treated with a solution of soda ash of about 5 Tw. at 3035 C. The materials may subsequently be rinsed in soft water.

Example 3 tion,

about 50-60" C. and maintained at this temperature until a test sample shows that acetone solubility has been'reached. The solution thus obtained is spun into a coagulating bath containing 10-15% aqueous acetic acid. The fixation of the 5 iron mordant may be effected by carrying the filaments into a subsequent treatment bath consisting of soda ash as described in the preceding example, or such a treatment may be applied discontinuously from the spinning operation. Alternatetively sodium phosphate may be added to the coagulating bath itself to effect the desired fixation.

The materials mordanted or weighted according to the present invention may be coloured by any suitable processes and with any suitable colouring matters, for example with mordant dyestuifs. As is already known materials made of or containing cellulose esters or ethers which have been weighted have an afiinlty for the direct cotton dyestufis and may therefore be dyed or coloured with such dyestuffs. If compatible therewith, the mordant or other dyestufis may be incorporated in baths used for fixing or precipitating the mordant or'weighting metals.

What I claim and desire to secure by Letters Patent is:-

1. In the manufacture of extruded products comprising organic derivatives of cellulose by spinning processes, the steps of introducing a mordant or weighting metal compound into the spinning solution, ,extruding said solution into a setting medium, fixing the metal in the extruded products by the application of a suitable fixing agent and'simultaneousw coloring the products.

2. In a process for the manufacture of mate- 35 rials comprising organic derivatives of cellulose by spinning processes, the stepsof introducing a mordant metal compound into the spinning solution, extruding the solution, and coagulating the same in a medium adapted simultaneously to fix 4n the metal in the coagulated materials and to color the materials.

3. In a process for the manufacture of materials comprising organic derivatives of cellulose by spinning processes, the steps 'of introducing a 45 mordant metal compound into the spinning soluextruding the solution, and coagulating the same in a medium adapted simultaneously to fix the metal in the coagulated materials and, in con- Junction with the mordant, to color the materials. "50

HENRY DREYFUS. 

